Stereoscopic three-dimensional (3D) content generally used for 3D movies or 3D broadcasts provides distance and depth perceptions through two stereoscopic images. 3D content is perceived when the brain analyzes and integrates stereoscopic images that viewers watch through the eyes. Stereoscopic 3D content may need to provide a natural 3D effect as if viewers see objects with both eyes in the real world.
Here, for a 3D broadcast service, right and left images for 3D broadcasting need transmitting. Right and left images generally use the same video format, while right and left images may have different aspect ratios in formats in hybrid 3D broadcasting in which the right and left images are transmitted through heterogeneous broadcast networks. When a 3D service is provided regardless of disagreeing aspect ratios, formats of the left and right images present on a display may have different aspect ratios, and such difference may bring about inconvenience to a user watching a 3D broadcast. Accordingly, there is needed a processing method for providing a user with a hybrid 3D broadcast using transmission formats of left and right images with different aspect ratios so that the user perceives a natural 3D effect.
In particular, to provide a stereoscopic 3D broadcast service, two different images from different viewpoints, right and left images, may need transmitting. In this case, the right and left images may generally have the same aspect ratio in terms of transmission format and display. However, in a hybrid 3D broadcast service in which one of the two viewpoint images is transmitted through a terrestrial 2D broadcast network and the other one is transmitted through a different broadcast network of a mobile network, a broadband network or a satellite network, the two viewpoints images may have different aspect ratios relating to transmission format and display due to different broadcast standards. These different aspect ratios may cause serious inconvenience to a user watching a composed 3D image, and accordingly a way of resolving this problem is needed.